Index: library/nx/nx.tcl
===================================================================
diff -u -r679a4d086fb9b8a728e0d33f5fa6520f2ce2f954 -r1beeb594c1cd9e222b6e1f419e9a6f5ec0713249
--- library/nx/nx.tcl	(.../nx.tcl)	(revision 679a4d086fb9b8a728e0d33f5fa6520f2ce2f954)
+++ library/nx/nx.tcl	(.../nx.tcl)	(revision 1beeb594c1cd9e222b6e1f419e9a6f5ec0713249)
@@ -1023,6 +1023,7 @@
     # multiplicty at the level of the ObjectParameter. We want to have
     # the same interface as on Attribute.
     set options ${:disposition}
+    #if {[info exists :elementtype]} {lappend options type=${:elementtype}}
     if {${:name} ne ${:methodname}} {lappend options arg=${:methodname}}
     if {${:required}} {
       lappend options required
@@ -1107,7 +1108,7 @@
   ::nsf::relation RelationSlot superclass ObjectParameterSlot
 
   createBootstrapAttributeSlots ::nx::RelationSlot {
-    {elementtype ::nx::Class}
+    {elementtype class}
     {nosetter false}
   }
 
@@ -1154,9 +1155,6 @@
         }
         set value [::nsf::dispatch $value -frame method ::nsf::self]
       }
-      if {![::nsf::is class ${:elementtype}]} {
-        error "$value does not appear to be of type ${:elementtype}"
-      }
     }
     set p [lsearch -exact $old $value]
     if {$p > -1} {